Firearms such as rifles normally include a relatively elongated barrel that is gripped by a user during firearm operation. Because the barrel may become hot with repeated firing, the firearm is normally equipped with a hand guard that is positioned about an exterior surface of the barrel. During operation, the user may grip the hand guard instead of the barrel to protect his hand from the heat.
The hand guard may be secured to the firearm using at least some existing components of the firearm. For example, the firearm usually includes a front sight base, which is used to sight the firearm, and a barrel nut, which is used to attach the barrel to the firearm. These components may also be employed to associate the hand guard with the firearm. More specifically, the hand guard may be positioned between the front sight base and the barrel nut, a forward end of the hand guard may fit into a hand guard cap adjacent the front sight base, and a rearward end of the hand guard may be positioned between the barrel nut and a delta ring. Such a configuration is described in U.S. Pat. No. 3,090,150 entitled “Hand Guard Construction”.
In some cases, the hand guard provided with the firearm may be replaced with a replacement hand guard. The replacement hand guard may have a range of configurations. For example, the replacement hand guard may have a rail system for mounting one or more accessories to the firearm, such as a scope, a grenade launcher, or a laser, among others. The replacement hand guard may also be free-floating, meaning spaced apart from the barrel in a radial direction to form an air gap about the barrel. The air gap may dissipate heat so that the user may grip the hand guard without being burned. The air gap also may provide a relief area for absorbing displacement caused by the grip of the user or the weight of an accessory, which may affect the direction of the projectile. The air gap also may reduce the impact of adding or removing accessories on the harmonics of the barrel, reducing the need to re-zero the firearm.
To install a replacement hand guard, the hand guard initially provided with the firearm may be removed, which typically requires retracting the delta ring, removing the rearward end of the hand guard from the barrel nut, removing the forward end of the hand guard from the hand guard cap, and separating the hand guard from the firearm. The replacement hand guard then may be installed on the firearm.
Some replacement hand guards may attach to both the hand guard cap and the barrel nut. However, such replacement hand guard members are not free-floating. Thus, when the user grasps the hand guard, or adds or removes accessories, the aim of the firearm may be disturbed.
Some replacement guards also may be relatively cumbersome to install. For example, it may be necessary to remove one or more of the front sight base, the hand guard cap, the barrel nut, and the delta ring. However, the user may not have the skills, tools, or authority to remove or adjust these components. For example, military and police personnel are often not permitted to remove these components of the firearm.
Some replacement hand guards are formed in a single piece that encircles the barrel of the firearm. Because such replacement hand guards cannot be slid over the front sight base and the hand guard cap, installing such a replacement hand guard requires either removing the front sight base and the hand guard cap or separating the barrel from the upper receiver of the firearm, which ultimately requires removing the front sight base, the hand guard cap, and the barrel nut.
Some replacement hand guards are installed using an attachment mechanism that secures the hand guard to the barrel nut. Typically, the attachment mechanism is a bulky structure that clamps the hand guard about the circumferential surface of the barrel nut. Such an attachment mechanism may be too large to fit between the barrel nut and the delta ring, and therefore the delta ring may be removed from the firearm to install the replacement hand guard in such cases.
Still other replacement hand guards may be securely attached to the firearm without removing components of the firearm. For example, some known replacement hand guards include an extension member that attaches to the upper receiver. These replacement hand guards change the layout of the weapon. For example, the height of the upper receiver may be increased, which may raise the line of sight of the user or affect the compatibility of the firearm with standard accessories. Also, these and other replacement hand guards may be relatively heavy. Therefore, a need exists for systems and methods for installing a hand guard on a firearm.